This invention relates to a series of substituted imidazopyrimidines and pharmaceutical compositions containing them. The compounds of the invention inhibit the production of a number of inflammatory cytokines, particularly TNF-xcex1 and IL-1xcex2. Compounds of this invention are useful in the treatment of diseases mediated by p38, such as rheumatoid arthritis, inflammatory bowel disease, septic shock, osteoporosis, osteoarthritis, neurodegenerative disorders, and AIDS-related diseases.
The inflammatory cytokines TNF-xcex1 and IL-1xcex2 play an important role in a number of inflammatory diseases such as rheumatoid arthritis (Dinarello et al., Curr. Opin. Immunol., 1991, 3: 941-8). Arthritis is an inflammatory disease which affects millions of people and can strike at any joint in the human body. Its symptoms range from mild pain and inflammation in affected joints, to severe and debilitating pain and inflammation. Although the disease is associated mainly with aging adults, it is not restricted to adults.
The most common arthritis therapy involves the use of nonsteroidal anti-inflammatory drugs (xe2x80x9cNSAID""sxe2x80x9d) to alleviate the symptoms. However, despite the widespread use of NSAID""s, many individuals cannot tolerate the doses necessary to treat the disease over a prolonged period of time. In addition, NSAID""s merely treat the symptoms of the disease without affecting the underlying cause. Other drugs such as methotrexate, D-pencillamine, gold salts, and Frednione are often used when patients fail to respond to NSAID""s. These drugs also have significant toxicities and their mechanisms of action remain unknown.
Receptor antagonists to IL-1xcex2 and monoclonal antibodies to TNF-xcex1 have been shown to reduce symptoms of rheumatoid arthritis in small-scale human clinical trials. In addition to protein-based therapies, there are small molecule agents which inhibit the production of these cytokines and have demonstrated activity in animal arthritis models (Boehm et al., J. Med. Chem., 1996, 39:3929-37). Of these small molecule agents, SB 203580 has proven effective in reducing the production of TNF-xcex1 and IL-1 in LPS-stimulated human monocyte cell lines with IC50 values of 50 to 100 nM (Adams et al., WO 93/14081, Jul. 23, 1993). In addition to this in vitro test, SB 203580 inhibits the production of the inflammatory cytokines in rats and mice at IC50 values of 15 to 25 mg/kg (Badger,et al, J. Pharm. Exp. Therap., 1996, 279:1453-61). Although human data are currently unavailable for SB 203580, monoclonal antibodies to TNF-xcex1 have proven efficacious in the treatment of rheumatoid arthritis (Elliot et al., Arthritis Rheum. 1993, 36: 1681-90). Due to SB 203580""s oral activity and potency in animal models, researchers have suggested that a compound with this profile has potential as a viable treatment for rheumatoid arthritis (Badger et al., J. Pharm. Exp. Therap., 1996, 279:1453-61).
SB 203580 and other small molecule agents reduce the production of inflammatory cytokines by inhibiting the activity of a serine/threonine kinase p38, which sometimes is referred to as CSBP, at an IC50 of 200 nM (Griswold et al., Pharm. Commun., 1996, 7:323-9). Although the precise role of this kinase is unknown, it has been implicated in both the production of TNF and the signaling responses associated with the TNF-xcex1 receptor.
WO 91/00092 discloses a method of inhibiting the production of interleukin-1 by monocytes and/or macrophages in humans by administering a diaryl-substituted imidazole fused to a second heterocyclic ring containing a nitrogen bridgehead atom, wherein the second ring may also contain sulfur, oxygen or an additional nitrogen atom, and may contain additional unsaturation.
WO 90/15534 and EP 0403251 disclose treatments of humans afflicted with a T Cell Viral (TIV) infection which comprises administering an effective amount of a monokine activity-reducing agent.
WO 91/19497 discloses a diaryl-substituted imidazole compound useful in dual inhibition of 5-lipoxygenase pathway-mediated diseases and cyclooxygenase pathway-mediated diseases. This compound is fused to a second unsaturated 5 or 6 membered heterocyclic ring containing a nitrogen bridgehead atom, wherein the second 5 membered ring also contains a sulfur or oxygen atom and the 6 membered ring may also contain an additional nitrogen atom.
Despite these known compounds and methods, there remains a need in the art for improved methods of reducing inflammatory cytokine production through inhibiting serine/threonine kinase p38 activity, and for related methods of treating and preventing arthritis and other inflammatory disorders.
This invention provides novel compounds which inhibit the in vitro activity of p38 in the nanomolar range as well as methods for making same. In addition, the compounds of the present invention inhibit the in vitro secretion of TNF-xcex1 and IL-1xcex2 in the nanomolar range. Animal models demonstrate the inhibition of LPS-induced TNF-xcex1 production. Demonstrated to have these biological activities by in vitro and in vivo assays described hereinafter are the compounds of the present invention as shown in Formula I: 
This invention also provides a pharmaceutical composition comprising the instant compound and a pharmaceutically acceptable carrier, as well as related synthetic methods.
This invention further provides a method of treating a subject suffering from a condition whose alleviation is mediated by the reduction of inflammatory cytokines whose actions contribute to the condition, which method comprises administering to the subject a therapeutically effective dose of the instant pharmaceutical composition.
This invention still further provides a method of inhibiting in a subject the onset of a condition whose alleviation is mediated by the reduction of inflammatory cytokines whose actions contribute to the condition, which method comprises administering to the subject a prophylactically effective dose of the instant pharmaceutical composition.
This invention provides a compound of Formula I, 
or a pharmaceutically acceptable salt thereof, wherein
(a) R1 is selected from NH2, C1-5alkylamino, diC1-5alkylamino, hydroxy, C1-5alkoxy, phenylmethylamino, heterocyclylmethyl, C1-5alkylcarbonylamino, and substituted phenylcarbonylamino, wherein
said phenylmethylamino and heterocyclylmethyl may be substituted on its phenyl moiety by one or more members selected from the group consisting of halogen, C1-5alkyl, C1-5alkoxy, arylC1-3alkylamino, Rxe2x80x2Rxe2x80x3NCHxe2x95x90Nxe2x80x94 and ORxe2x80x2xe2x80x3, the Rxe2x80x2, Rxe2x80x3, and Rxe2x80x2xe2x80x3 being independently selected from H, C1-5alkyl, phenylmethyl, substituted phenylmethyl, xcex1-alkyl-phenylmethyl, substituted xcex1-alkyl-phenylmethyl, heterocyclylmethyl, and substituted heterocyclylmethyl;
(b) Y is selected from the group consisting of H, halogen, heterocycle, OR4, SR4, NR4, and NR4R5, wherein
R4 and R5 are independently selected from H, heterocyclyl, C3-5carbocycle, phenyl, xcex1-alkyl-phenylC1-5alkyl, straight or branched alkyl optionally substituted with R, NR, N(R)2, C3-5carbocycle, phenyl or substituted phenyl, wherein (i) R is H, halogen, C1-5alkyl, phenyl methyl, substituted phenyl methyl, SO2Ph, pyridyl, or pyridyl methyl, and (ii) said phenyl, heterocyclyl, and xcex1-alkyl-phenylC1-5alkyl may be substituted by one or more members selected from the group consisting of halogen, C1-5alkyl, C1-5alkoxy, arylC1-3alkylamino, phenyl methyl, substituted phenyl methyl, Rxe2x80x2Rxe2x80x3NCHxe2x95x90Nxe2x80x94 and ORxe2x80x2xe2x80x3 as defined in (a) hereof;
(c) R2 is one to five members independently selected from the group consisting of halogen, trifluoromethyl, xe2x80x94NCH2PH, C1-5alkyl, and C1-5alkoxy;
(d) R3 is H or, taken together, an aromatic ring; and
(e) X is N or CH.
In one embodiment of the instant compound, R1 is NH2. In another embodiment, R2 is a member selected from the group consisting of halogen, trifluoromethyl, xe2x80x94NCH2PH, and C1-5alkoxy. In yet another embodiment, Y is NR4 and R4 is phenylmethyl. In still another embodiment, X is CH.
Unless specified otherwise, the term xe2x80x9calkylxe2x80x9d refers to a straight, branched or cyclic substituent consisting solely of carbon and H with no unsaturation. The term xe2x80x9calkoxyxe2x80x9d refers to O-alkyl where alkyl is as defined supra. The term xe2x80x9caromatic ringxe2x80x9d refers to a 5- to 6-membered ring containing a 6-electron delocalized conjugated pi bonding system such as phenyl, furanyl, and pyrrolyl. The term xe2x80x9carylxe2x80x9d includes mono and fused aromatic rings such as phenyl, naphthyl, diphenyl, fluorophenyl, difluorophenyl, benzyl, benzoyloxyphenyl, carboethoxyphenyl, acetylphenyl, ethoxyphenyl, phenoxyphenyl, hydroxyphenyl, carboxyphenyl, trifluoromethylphenyl, methoxyethylphenyl, acetamidophenyl, tolyl, xylyl, dimethylcarbamylphenyl and the like. The term xe2x80x9chaloxe2x80x9d means fluoro, chloro, bromo and iodo. The symbol xe2x80x9cPhxe2x80x9d refers to phenyl. The term xe2x80x9cheterocyclylxe2x80x9d, xe2x80x9cheterocyclexe2x80x9d or xe2x80x9cheterocyclic residuexe2x80x9d represents a single or fused ring having at least one atom other than carbon as ring member, e.g. pyridine, pyrimidine, oxazoline, pyrrole, imidazole, morpholine, furan, indole, benzofuran, pyrazole, pyrrolidine, piperidine, and benzimidazole.
Substituted heterocyclylmethyl and substituted phenylmethyl have substituents such as halogen, C1-5alkyl, C1-5alkoxy, arylC1-3alkylamino, Rxe2x80x2Rxe2x80x3NCHxe2x95x90Nxe2x80x94, and ORxe2x80x2xe2x80x3 wherein Rxe2x80x2, Rxe2x80x3, and Rxe2x80x2xe2x80x3 are independently selected from H, C1-5alkyl, phenylmethyl, substituted phenylmethyl, xcex1-alkyl-phenylmethyl and substituted xcex1-alkyl-phenylmethyl, heterocyclylmethyl, and substituted heterocyclylmethyl.
The term xe2x80x9cFCSxe2x80x9d represents fetal calf serum, xe2x80x9cTCAxe2x80x9d represents trichloroacetic acid, and xe2x80x9cRPMIxe2x80x9d represents the medium from the Roswell Park Memorial Inst. (Sigma cat #R0833). xe2x80x9cIndependentlyxe2x80x9d means that when there is more than one substituent, the substituents may be different. xe2x80x9cDMExe2x80x9d refers to ethylene glycoldimethyl. The term xe2x80x9cNaHMDSxe2x80x9d refers to sodium hexamethyldisilazide.
The phrase xe2x80x9cpharmaceutically acceptable saltxe2x80x9d denotes salts of the free base which possess the desired pharmacological activity of the free base and which are neither biologically nor otherwise undesirable. These salts may be derived from inorganic or organic acids. Examples of inorganic acids are hydrochloric acid, hydrobromic acid, hydroiodic acid, perchloric acid, nitric acid, sulfuric acid and phosphoric acid. Examples of organic acids are acetic acid, propionic acid, glycolic acid, lactic acid, pyruvic acid, malonic acid, succinic acid, malic acid, maleic acid, maieic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, oxalic acid, pamoic acid, saccharic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, methyl sulfonic acid, salicyclic acid, hydroethanesulfonic acid, benzenesulfonic acid, 2-naphthalenesulfonic acid, p-toluenesulfonic acid, cyclohexanesulfamic acid and the like.
Where the compounds according to this invention have one or more stereogenic centers, it is to be understood that all possible optical isomers, antipodes, enantiomers, and diastereomers resulting from additional stereogenic centers that may exist in optical antipodes, racemates and racemic mixtures thereof are also part of this invention. The antipodes can be separated by methods known to those skilled in the art such as, for example, fractional recrystallization of diastereomeric salts of enantiomerically pure acids. Alternatively, the antipodes can be separated by chromatography in a Pirkle-type column.
The following compounds are exemplary of the present invention:
Compound 1: 2-(4-fluorophenyl)-3-(4-pyridinyl)-imidazo[1,2-a]pyrimidin-7-amine; 
Compound 2: 2-(3-fluorophenyl)-3-(4-pyridinyl)-imidazo[1,2-a]pyrimidin-7-amine;
Compound 3: 2-(4-fluorophenyl)-3-(4-quinolinyl)-imidazo[1,2-a]pyrimidin-7-amine; 
Compound 4: 2-(3-chloro-4-fluorophenyl)-3-(4-pyridinyl)-imidazo[1,2-a]pyrimidin-7-amine;
Compound 5: 2-phenyl-3-(4-pyridinyl)-imidazo[1,2-a]pyrimidin-7-amine; 
Compound 6: 2-(4-fluorophenyl)-3-[2-[(phenylmethyl)amino]4-pyridinyl]-imidazo[1,2-a]pyrimidin-7-amine;
Compound 7: 3-(4-pyridinyl)-2-[3-(trifluoromethyl)phenyl]-imidazo[1,2-a]pyrimidin-7-amine; 
Compound 8: 3-[2-[(phenylmethyl)amino]4-pyridinyl]-2-[3-(trifluoromethyl)phenyl]-imidazo[1,2-a]pyrimidin-7-amine;
Compound 9: 3-[2-[[(1S)-1-Phenylethyl]amino]4-pyrimidinyl]-2-[3-(trifluoromethyl)phenyl]imidazo[1,2-a]pyrimidin-7-amine; 
Compound 10: 2-(4-Fluorophenyl)-3-[2-(methylthio)-4-pyrimidinyl]imidazo[1,2-a]pyrimidin-7-amine;
Compound 11: 3-[2-(Methylthio)-4-pyrimidinyl]-2-[3-(trifluoromethyl)phenyl]imidazo[1,2-a]pyrimidin-7-amine; 
Compound 12: 2-(3-Fluorophenyl)-3-[2-(methylthio)-4-pyrimidinyl]imidazo[1,2-a]pyrimidin-7-amine;
Compound 13: 3-(4-Pyrimidinyl)-2-[3-(trifluoromethyl)phenyl]imidazo[1,2-a]pyrimidin-7-amine; 
Compound 14: 2-Phenyl-3-[2-(1-piperidinyl)-4-pyrimidinyl]imidazo[1,2-a]pyrimidin-7-amine;
Compound 15: 3-[2-(Methylthio)-4-pyrimidinyl]-2-phenylimidazo[1,2-a]pyrimidin-7-amine; 
Compound 16: 2-Phenyl-3-(4-pyrimidinyl)imidazo[1,2-a]pyrimidin-7-amine;
Compound 17: 3-[2-(Methylsulfonyl)-4-pyrimidinyl]-2-phenylimidazo [1,2-a]pyrimidin-7-amine; 
Compound 18: 3-[2-(Methylsulfonyl)-4-pyrimidinyl]-2-[3-(trifluoromethyl)phenyl]imidazo[1,2-a]pyrimidin-7-amine;
Compound 19: 2-Phenyl-3-[2-[[(1S)-1 -phenylethyl]amino]4-pyrimidinyl]imidazo[1,2-a]pyrimidin-7-amine; 
Compound 20: 3-[[[(4-Methoxyphenyl)methyl]amino]-4-pyrimidinyl]-2-phenylimidazo[1,2-a]pyrimidin-7-amine;
Compound 21: 2-(4-Fluorophenyl)-3-[3-[[(1S)-1-phenylethyl]amino]-4-pyridinyl]imidazo[1,2-a]pyrimidin-7-amine; 
Compound 22: 3-[2-[[(1S)-1-Cyclohexylethyl]amino]-4-pyrimidinyl]-2-(4-fluorophenyl)imidazo[1,2-a]pyrimidin-7-amine;
Compound 23: 3-(2-Methoxy-4-pyrimidinyl)-2-phenylimidazo[1,2-a]pyrimidin-7-amine; 
Compound 24: 2-(4-Fluorophenyl)-3-(4-pyrimidinyl)imidazo[1,2-a]pyrimidin-7-amine;
Compound 25: 2-(3-Chlorophenyl)-3-(4-pyridinyl)imidazo[1,2-a]pyrimidin-7-amine; 
Compound 26: 3-(2-Bromo-4-pyridinyl)-2-(4-fluorophenyl)imidazo[1,2-a]pyrimidin-7-amine; and
Compound 27: 3-(2-Bromo-4-pyridinyl)-2-[3-(trifluoromethyl)phenyl]imidazo[1,2-a]pyrimidin-7-amine. 
This invention also provides a pharmaceutical composition comprising the instant compound and a pharmaceutically acceptable carrier.
Pharmaceutical compositions containing the compound of the present invention as the active ingredient in intimate admixture with a pharmaceutical carrier can be prepared according to conventional pharmaceutical techniques. The carrier may take a wide variety of forms depending on the form of preparation desired for administration, such as topical administration and systemic administration including, but not limited to, intravenous infusion, oral, nasal or parenteral. In preparing the compositions in oral dosage form, any of the usual pharmaceutical carriers may be employed, such as water, glycerol, glycols, oils, alcohols, flavoring agents, preservatives, coloring agents, syrup and the like in the case of oral liquid preparations (for example, suspensions, elixirs and solutions); or carriers such as starches, sugars, methyl cellulose, magnesium sterate, dicalcium phosphate, mannitol and the like in the case of oral solid preparations (for example, powders, capsules and tablets). All excipients may be mixed as needed with disintegrants, diluents, granulating agents, lubricants, binders and the like using conventional techniques known to those skilled in the art of preparing dosage forms.
The preferred route of administration is oral administration. Because of their ease in administration, tablets and capsules represent an advantageous oral dosage unit form, in which case solid pharmaceutical carriers are obviously employed. If desired, tablets may be sugar-coated or enteric-coated by standard techniques. For parenterals, the carrier will usually comprise sterile water, though other ingredients, for example, to aid solubility or for preservative purposes, may be included. Injectable suspensions may also be prepared, in which case appropriate liquid carriers, suspending agents and the like may be employed.
As used in this invention, the term xe2x80x9ccytokinexe2x80x9d refers to the proteins TNF-xcex1 and IL-1xcex2. Cytokine-related disorders are diseases of humans and other mammals where the overproduction of cytokines causes the symptoms of the disease. The overproduction of the cytokines TNF-xcex1 and IL-1xcex2 has been linked to a number of diseases.
The compounds of the present invention inhibit the production of TNF-xcex1 and IL-1xcex2. Thus, this invention further provides a method of treating a subject suffering from a condition whose alleviation is mediated by the reduction of inflammatory cytokines whose actions contribute to the condition, which method comprises administering to the subject a therapeutically effective dose of the instant pharmaceutical composition. As used herein, the term xe2x80x9csubjectxe2x80x9d includes, without limitation, any animal or artificially modified animal. In the preferred embodiment, the subject is a human.
This invention still further provides a method of inhibiting in a subject the onset of a condition whose alleviation is mediated by the reduction of inflammatory cytokines whose actions contribute to the condition, which method comprises administering to the subject a prophylactically effective dose of the instant pharmaceutical composition.
In one embodiment, the condition is selected from the group consisting of arthritis, inflammatory bowel disease, septic shock, osteoporosis, osteoarthritis, neuropathic pain, HIV replication, HIV dementia, viral myocarditis, insulin-dependent diabetes, non-insulin dependent diabetes, periodontal disease, restenosis, alopecia areta, T-cell depletion in HIV infection or AIDS, psoriasis, acute pancreatitis, allograft rejection, allergic inflammation in the lung, atherosclerosis, multiple sclerosis, cachexia, Alzheimer""s disease, stroke, Crohn""s disease, ischemia, congestive heart failure, pulmonary fibrosis, hepatitis, glioblastoma, Guillain-Barre Syndrome, and systemic lupus erythematosus. In the preferred embodiment, the condition is rheumatoid arthritis.
As used herein, xe2x80x9ctreatingxe2x80x9d a disorder means eliminating or otherwise ameliorating the cause and/or effects thereof. xe2x80x9cInhibitingxe2x80x9d the onset of a disorder means preventing, delaying or reducing the likelihood of such onset. Likewise, xe2x80x9ctherapeutically effectivexe2x80x9d and xe2x80x9cprophylactically effectivexe2x80x9d doses are doses that permit the treatment and inhibition, respectively, of a disorder. Methods are known in the art for determining therapeutically and prophylactically effective doses for the instant pharmaceutical composition. The effective dose for administering the pharmaceutical composition to a human, for example, can be determined mathematically from the results of animal studies.
In one embodiment, oral doses of the instant compounds range from about 0.05 to about 100 mg/kg, daily. In another embodiment, oral doses range from about 0.05 to about 50 mg/kg daily, and in a further embodiment, from about 0.05 to about 20 mg/kg daily. Infusion doses can range, for example, from about 1.0 to 1.0xc3x97104 xcexcg/kg/min of instant compound, admixed with a pharmaceutical carrier over a period ranging from several minutes to several days. For topical administration, the instant compound can be mixed with a pharmaceutical carrier at a concentration of, for example, about 0.1 to about 10% of drug to vehicle.
Finally, this invention provides processes for preparing the instant compounds. These compounds can be prepared as shown below from readily available starting materials and/or intermediates following processes well known in the art.
This invention will be better understood by reference to the Experimental Details that follow, but those skilled in the art will readily appreciate that these are only illustrative of the invention as described more fully in the claims which follow thereafter. Additionally, throughout this application, various publications are cited. The disclosure of these publications is hereby incorporated by reference into this application to describe more fully the state of the art to which this invention pertains.
Compounds of Formula I in which R1 is NH2, and R3and Y are H may be prepared by Scheme I. A starting compound of type 1a, such as 4-methyl pyridine or 4-methyl quinoline, may be stirred with a benzoic ester of type 1b and two equivalents of a suitable hindered base, such as sodium hexamethyldisiiazide in a suitable solvent such as THF at room temperature to give the enolate of 1c which is then brominated to type 1d. An intermediate of type 1d may be further reacted with 2,6-diaminopyrimidine to give a compound of Formula I in which R1 is NH2 and Y is H. 
Although the illustrated method produces a compound of Formula I where R1 is NH2, X is CH, and Y is H, this scheme may also be used to produce other compounds of the invention.
Scheme II shows how to make compounds of Formula I wherein X is N, and Y, R2 and R3 are defined as hereinabove. 
Scheme II shows how to make compounds of Formula I wherein X is CH, Zxe2x80x2 is F, Cl or Br, and Y, R2 and R3 are as defined hereinabove. 
Scheme IV shows how to make compounds of Formula I wherein X is CH, Y is NR4 and R4 is defined as hereinabove. 